I searched all over the lens forum and saw a lot of articles on this subject but non of them addressed what I needed. So if I'm being redundant please forgive me. I have a EF 70-200/2.8 L IS USM with a EF 2x II Extender, mounted on a 40D. With this set up I get 5.6 in the morning shooting beautiful Red Cardinals. I gain the extra lighting I need by using compensation and it works fine. BUT...I would like to have more reach. I'm shooting approx. 30' - 40' away. I would love to get a 500mm or a 600mm lens and use with the extender but don't have that extra cash. I've read a lot about different set ups, using tubes, diopters etc., and quite frankly I don't know enough to understand it all and connect the dots. And besides, a lot of that info. was concerning Macro shooting. So, with this camera set up of mine, what could I add (if anything) to this rig to increase my reach and get in closer? If you could please try to be specific so I can understand. Thank you so much in advance.